Gear-grinding machine



J. H. MACALPINE GEAR GRINDING MACHINE Aug 25, l 925.

Filed Nov. 50, 1920 4 Sheets-Sheet 1 INVENTOR. J. H.Macc1lpine BY @CM ATTORNEY 1,551,038" .1. H. MACALPINE GEAR GRINDING MACHINE Filed Nov. 30, 1920 V4 Sheets-Sheet 2 Aug. 25., 1925.

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Aug. '25. 1925.

' J. H. MACALPINE GEAR GRINDING MACHINE 4 Sheets-Sheet 4 Filed Nov. 50, 1920 YINVEN BY a ATTORNEY Patented Aug. 25, 1925.

UNITED STATES PATENT OFFICE.

JOHN H. MACALPINE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE WEST- INGHOUSE GEAR. AND DYNAMOMETER COMPANY, OF EAST PITTSBURGH, PENN SYLVANIA, A CORPORATION OF PENNSYLVANIA.

GEAR-GRINDING MACHINE.

Application filed November 30, 1920. Serial No. 427,304.

To all whom it may concern.

Be it known that I, JOHN H. MAoAL- PINE, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Gear-Grinding Machines, of which the following is a specification.

This invention relates to gear grinding machines employed for correcting errors in the spacing and form of teeth of gearing, especially of the double helical type.

Another object of the 'irrvention is to produce a gear grinding machine in which the gear and pinion or pinions with which the gear is to operate may be simultaneously ground for the purpose of correcting any errors in the cutting of the gear teeth so that the tooth pressure exerted by the pinion is uniformly distributed throughout the length of the teeth of the gearings and so that the load upon each tooth of the gear is uniform.

Another object is to produce a grinding machine in which a gear and pinion may be readily adjusted as the grinding opera-- tion progresses.

Another object is to produce a grinding machine in which the gear and pinion may be held against relative longitudinal displacement during the grinding operation so as to insure accurate grinding of the teeth of the gear and pinion.

The machine for supporting the gears is provided with a base of such rigidity and strength that the ordinary strains caused by the rotation of the gears will not cause the slightest deflection which would result in relative axial displacement of the gear and pinions. Relative longitudinal movement of the gear and pinion or pinions is prevented by end thrust bearings, preferably having anti-friction elements, capable of preventing any longitudinal movement of the shaft in either direction. The bearings for the pinion are, however, constructed so that they can be moved relatively with respect to the base and firmly secured thereto after the pinion has been properly adjusted with respect to the gear.

The machine embodying the features of construction referred to above is illustrated in the accompanying drawings wherein Fig. 1 is a plan view of the grinding machine showing practically one half of the base and gear cut away.

Fig. 2 is an irregular vertical section plan taken on the line IIII of Fig. 1.

Fig. 3 is a transverse section of the pinion bearing taken on the line IIIIII of Fig. 1.

Fig. 1 is a diagrammatic view showing the rocker construction for supporting the race rings of the thrust bearing.

Fig. 5 is a diagrammatic view of structure shown in Fig. 1.

Fig. 6 is a diagrammatic view showing the application of two pinions to a single gear.

Referring to the drawings, the apparatus includes a base 4;, preferably cast, having walls of unusual thickness arranged and distributed so as to form a bearing base of great strength and rigidity. The base is provided with hearing pedestals 5 preferably integrally cast with the base and pro vided with split bearing bushings 6 which are adapted to receive the shaft 7 of the gear 8. The bushings are adapted to be retained in position by means of bearing caps 9 which are preferably bolted to the bearing pedestals 5.

One of the pedestals 5, for example the one illustrated in Fig. 2, is provided with a thrust bearing chamber 10 in which a thust bearing adapted to prevent longitudinal displacement of the shaft is located. This bearing includes a thrust collar 11 which is slipped longitudinally on the end of the shaft 7 and which abuts a shoulder 12 provided upon the shaft. The thrust collar is held against longitudinal displacement by means of a threaded nut 13 which is tightly secured upon a screw-threaded end 14;.

A race ring 17 is arranged on each side of the thrust collar 11 and anti-friction elements, such as the balls or rollers 18, are disposed between each race ring and the thrust collar. The balls or rollers are preferably spaced by cages 19.

The race rings 17 are supported within supporting seats 20 carried within the chamber 10, one engaging the pedestal shoulder 15 and the other or outermost seat being retained in position by the cap 16. Between each annular race ring 17 and its respective supporting seat 20 is disposed an annular row of interengaging fulcrum or leveling blocks 21 provided for the purpose of uniformly distributing the load imposed upon the race ring by the ball bearings 18. As the construction of the race ring and fulcrum blocks of the Kingsbury thrust bearing is well known to those skilled in the art, no attempt is made here to enter into the details of the construction. Any thrust bearing which will uniformly distribute the pressure imposed upon the race ring so as to compensate for minute discrepancies in the diameters of the balls or rollers, and imperfections in the thrust collar or ball race, may be used to advantage in maintaining the shaft in fixed longitudinal position with respect to the bearings, and in carrying out the herein described process.

It is not desirable that there should be relative longitudinal movement of the gear and pinion, even to the extent of one thousandth part of an inch. For this reason the base is made sufliciently rigid to withstand, without the least deflection, the strains imposed thereon during the grinding operation, and thrust bearings are provided for preventing the slightest longitudinal movement of the gear.

It will be seen that by the use of thrust bearings, with means for compensating for imperfections in the balls or races, forces tending to cause longitudinal displacement of the shafts, such as are due to discrepancies in the diameters of the balls or rollers, and to the fact that the faces of the thrust collars may not be exactly parallel, are neutralized. Consequently, assuming that the bearings are tight, the shaft may rotate without the least endwise movement regardless of the imperfections referred to. In order to maintain the bearings tight, so that there may be no lost motion caused by wearing of the bearings, the outer seat is usually engaged by the end cap 16 and thus constantly forced toward the bearings.

The end cap 16 is adapted to telescope into the bearing chamber 10 so as to make an air tight closure therefor and is yieldingly held against the outer seat 20 by means of a series of helical springs 22 disposed between the nuts 23 threaded upon studs 24. While but two of such nuts and studs are shown in Fig. 2 for the purpose of illustration, it will be understood that any desired number will be equally spaced around the end plate. Tension of the springs may be adjusted by means of the nuts 23 and. it will be understood that the tension of the springs will be sufficient to withstand with compression any normal end thrust imposed upon the thrust bearing during the normal grinding operation. It will be seen that the slightest wear of the thrust bearing will be immediately taken up by the inward movement of the end cap 16 under the influence of the springs. As the thrust collar l1 prevents movement of the shaft in either longitudinal direction, it is only necessary to provide the thrust collar at one end of the shaft. Consequently, the bearing for the opposite end of the shaft carrying the coupling flange 2 1 may be of any preferred form, and such bearing is therefore not illustrated in detail.

Lubricant is supplied to the journal and thrust bearing through an oil inlet 25 and flows into an annular chamber 26 surrounding the divided bushing 6. Oil flows to the shaft ournal through the ports 27 and flows in opposite direction therefrom, the oil flowing to the right entering the thrust chamber 10 and that flowing toward the gear entering an annular groove 28, the excess flowing through the passage 30 to a drain pipe 29. Oil passing through the chamber 10 is drained through an outlet port 31 which may be connected with any suitable oil circulating system. The lubricant supplied to the bearings is preferably forced therethrough under pressure supplied by any suitable circulating pump, not shown.

The pedestal or bearing block 32 for supporting the pinion 32, with which the gear is to be ground and corrected, is preferably a solid casting provided with three integrally cast bearings 33, 3 1, and 35, the last being provided with a thrust bearing chamber 10 adapted to contain a thrust bearing, similar in all respects, except in size and proportions, to the thrust bearing described in connection with the gear 8, for the purpose of preventing longitudinal displacement of the pinion with respect to the pedestal. The pinion shaft 36, Fig. 2, is provided with an extension 37 which is secured to the end of the shaft by any preferred means. The extension is provided with an integral thrust collar 11 which serves for the same purpose as the collar 11 mounted on the end of the gear shaft 7. Anti-friction bearings includ ing balls 18, race rings 17, race ring seats 20 and fulcrum blocks 21, similar in func tion to those employed in preventing longitudinal movement of the shaft 7, are provided in the bearing chamber 10. The chamber is closed with an end plate 16 yieldingly held against the seat 20 by means of helical springs 22 disposed between the end plate 16 and the threaded nuts 23 screwed upon studs 24 mounted on the thrust bearing housing 38.

It will be observed, by reference to Fig. 2, that the bearing housing 38 is adapted to be bolted to the pedestal 32 after the extension 37 has been applied to the shaft 36, and in this respect the housing differs from that enclosing the thrust bearing applied to the shaft 7 which is integral with the base and which is completed by the cap 9. The thrust bearing for the pinion is lubricated in a pedestal or hearing block.

manner similar to the thrust bearing for the gear. Oil is forced to the journal of the pinion shaft through the port and after passing the journal is drained off through a passage from a point adjacent the pinion and through a port 31 after it is passed through the bearing chamber 10.

The pinion pedestal or bearing block 32 is adjustably mounted upon a fiat bed 39 adapted to support the pinion horizontally with its axis preferably parallel to that of the gear 15. The pedestal or hearing block is constructed so that it has great strength and rigidity and is mounted upon the bed 39 between two pairs of lugs 40 and 41 which are provided with adjustment screws 42 and 43, respectively. The screws 42 and 43 are provided for the purpose of maintain ing the pedestal or hearing block in any adjusted position. Shoes or gibs 44 are disposed between the pedestal or bearing block and screws so as to permit of longitudinal movement of the pedestal while it is held against lateral displacement in a direction toward or away from the axes of the gears by the said screws.

The pedestal or hearing block is adapted to be adjusted longitudinally by means of finely threaded adjustment screws 45, one of which is shown in section in Fig. 2, and as mounted in a lug 46 cast integrally on the base 4. As shown in Fig. 1, the screws are disposed directly beneath the axis of the pinion and engage seats 47 rovided on the lify adjusting the screws 42, 43, and 45, the pedestal or hearing block supporting the pinion may be moved laterally and longitudinally to any desired position and the pinion may there by be adjusted in proper operative position to the gear.

Vertical displacement of the pedestal or hearing block is prevented by means of a plurality of bolts 48, Figs. 1 and 3, which project upwardly through clearance slots 49 and 50 in the base and pedestal, respectively. In order that the pedestal or hearing block may be adjusted in a horizontal plane without the necessity of loosening the bolts, the pedestal or hearing block is held down upon the base 4 under tension by means of helical springs 51 disposed between the bolt heads and the under side of the base late. It will be seen that, owing to the c earance provided between'bolts and slots, the pedestal or bearing block may be adjusted within certain limits in all directions in the horizontal plane. The tension of the springs 51 is regulated by means of the nuts 52 threaded upon the upper ends of the bolts 48 and which engage washers 52 disposed between the nuts and the upper face of the pedestal 32. It will be understood that while but one pinion pedestal is shown in Fig. 1, another pedestal may be mounted upon the opposite side of the gear in which case a brake could be advantageously applied to the second pinion.

Plane level surfaces 53 are disposed at convenient places upon the base and pedestal or pedestals and are adapted to receive a separate level for the purpose of facilitating aligning of the gear or pinion or pinions in the same plane as it is desirable in carrying out the process that the axes of the gear and pinion or pinions be substantially parallel.

A brake is associated with shaft 7 of the gear of the construction of Fig. 1, see Fig. 5. The brake serves to impose a load on the gear shaft thereby effecting tooth pressure sufficiently high to facilitate the grinding of the teeth.

While I have shown the thrust bearings for the gear and pinion shafts at opposite sides, it will be obvious that these hearings might be arranged on the same side without varying or affecting the principle of my invention.

In carrying out the process, the gear is first placed in the bearings and a thrust bearing is provided so as to prevent longitudinal displacement of the gear. The pinion is then placed in the pedestal bearings and the thrust bearing therefor applied so as to prevent relative longitudinal movement of the pinion with respect to the pedestal. The pedestal is then adjusted so as to bring the pinion into proper operative relation with the gear, that is to a position determined by trial, observing the grinding, wherein the pinion and gear axes are approximately parallel.

After the pinion has been adjusted, it is connected with any suitable driving agent by means of a feathered shaft 54 in such a manner that the pinion may be moved with respect to the driving agent, not shown. After the gear has been driven by the pinion it may be found that the helices or teeth of one side of the gear are ground more than the helices or teeth of the other side, in which event the pedestal supporting the pinion is moved longitudinally by means of the adjustment screws 45, the screws 42 and 43 being adjusted as may be required. This adjustment may be made while the pinion is rotating and when it is found that the helices of each half of the gear are being ground uniformly, the grinding operation is continued to completion without further longitudinal adjustment of the pinion. The driver is rotated in opposite directions in order to grind all the tooth faces. By this process, gears and pinions may be accurately corrected.

It will be understood that a load of some kind should be imposed on the gear in order that desirable pressures may exist between the teeth. If two pinions are in mesh with the same gear, this result is conveniently achieved by using a brake in connection with one pinion and driving the other. See Fig. 6. lVith a single pinion engaging a single gear, as in Fig. 1, a brake or other load imposing expedient should be used, which may be conveniently related to the flange 2%, as shown in Fig. 5. It will be obvious that the resisting load might be a generator or other means.

Although, I have shown my gear grinder in combination with double-row helical teeth of the usual reduction-gear type, it is obvious that it may be used with any pair of gear members having gear elements oppositely inclined with reference to the end faces of the members, or it may be used with spur gears having straight or curved teeth.

It will be obvious that the principle of my invention may be utilized by having any desired number of pinions mesh with the gear. In Fig. 1, I have shown a single pinion, whereas in Fig. 5 two pinions are shown. Another desirable arrangement is that of four pinions engaging the gear. One, two or four pinions are itrequently used in connection with a common gear depending on the number of turbine shafts connected to the reduction gear.

From the foregoing, it will be understood that it is desirable to have some means to insure sufficient tooth pressure. If one pinion only is used, then, as shown in Fig. 6, power may be applied to the pinion and a brake applied to the gear; however, it is obvious that this arrangement might be reversed. lVith two pinions, it is preferred to apply power to one and a brake to the other, but it is apparent that power might be applied to the gear and brakes applied to the pinions. In order to assure tooth pressures with an arrangement having a greater number of pinions meshing with a single gear, it is obvious that any suitable connection of the power and brake or brakes with the gear and pinions may be utilized. It is merely fundamental that each pinion be correctly placed and maintained relatively to its cooperating gear and that proper tooth pressures between each pinion and the gear be developed in some way.

lVhile I have shown my invention in a number of forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications. without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the a,- pended claims.

lVhat I claim is:

1. A gear grinding machine comprising a rigid base, bearings for supporting the gear rigidly mounted 011 the base, means for preventing longitudinal displacement of the gear in either direction, a pinion adapted to mesh with the gear, bearings for the pinion adjustably mounted on the base whereby the pinion may be properly adjusted with respect to the said gear, means for anchoring the said bearings to the said base so that it is held immovable with respect to the gear, and means carried by the bearings for preventing longitudinal movement of the pinion in either direction.

2. A gear grinding machine comprising a rigid base having supporting bearings for a gear and means for preventing longitudinal displacement of the gear, comprising a thrust bearing adapted to positively prevent longitudinal movement of the gear in one direction and to yieldingly oppose longitu dinal movement of the gear in opposite direction.

3. A gear grinding machine comprising a rigid base having supporting bearings for a gear provided with a thrust collar and means for preventing longitudinal displacement of the gear comprising means engaging one face of the thrust collar whereby longitudinal movement of the gear in one direction is positively prevented and means engaging the opposite face of the said collar adapted to yieldingly oppose longitudinal movement of the gear in the opposite direction.

A gear grinding machine comprising a rigid base having supporting bearings for rotatively supporting a gear shaft, a gear on the shaft, a thrust collar mounted upon the shaft, anti-friction bearings between the thrust collar and the said bearings opposing the thrust of the shaft in one direction, anti-friction bearings engaging the collar for opposing the thrust of the shaft in the opposite direction and means for yieldingly holding the anti-friction bearings in operative relation with the said collar.

5. A gear grinder for double-row helical gearing comprising a rigid base, bearings carried by the base to maintain the position of a first gear member, a pedestal, bearings carried by the pedestal and adapted to maintain the position of a second gear member with reference thereto, and adjustable means for securing the pedestal to the base for properly positioning the gear and pinion members relatively and for retaining the pinion immovably with respect to the gear.

6. A gear grinder for spur gearing, a rigid base, bearings including a thrust hearing to maintain with precision the position of a first gear member, a pedestal member slidable on the rigid base, bearings carried by the pedestal member including a thrust bearing to maintain with precision the posi; tion of a second gear member with reference to the pedestal, means to adjust the pedestal member in order to properly mesh the gear members, and means to move the pedestal under pressure but allowing relative movement therebetween, bearings carried by the bearing support member and adapted to maintain with precision a second gear member in relation thereto, adjustably securing means for the bearing support member for varying the distance between the axes of the two sets of bearings for bringing said axes into substantial parallelism and for maintaining a fixed distance between the centers of the two sets of bearings, level support means carried by the base member to assist in bringing the axes into substantial parallelism and means to move the bearing support member whereby uniform grinding of the gear members may be assured.

8. In a gear grinder for gearing with reversely inclined teeth, a rigid member adapted to rotatably support a first gear member, a support member adapted to rotatably support a second gear member, means to adjust laterally the support member relatively to the rigid member, and means to shift the support member whereby uniform grinding of the reversely inclined teeth is assured.

9. A gear grinder comprising a rigid base member, bearings carried thereby, a shaft mounted in the bearings, motionrcsisting means acting on said shaft, a gear member on the shaft, a member adjustable with reference to the base member bearings car-- ried by the member, connecting means for the base member and the member maintaining the axis of the bearings of the member in a plane substantially parallel to the axis of the base member bearings, a shaft mounted in the member bearings, a pinion member on the shaft adapted to mesh with the gear member, means for maintaining with precision the position of each shaft with reference to its member, and adjusting means associated with the member to secure lateral adjustment of the member and a proper relationship of the pinion and gear members for meshing and to secure adjustment of the member in order to obtain uniform grinding of the pinion and gear members.

10. A gear grinder comprising a rigid base member, bearings carried thereby, a gear member j'ournaled in the bearings, means to maintain with exactness the longitudinal position of the gear member relatively to the base member, motion-resisting means associated with the gear member, a pedestal member resting on the base member, bearings carried by the pedestal member, a pinion member journaled in the bearings of the pedestal member and adapted to mesh with the gear member, means to maintain with exactness the longitudinal position of the pinion member relatively to the pedestal, means carried by the base member and acting on the pedestal to se cure lateral. adjustment of the latter for properly meshing the teeth, and other means carried by the base member to adjust the pedestal longitudinally.

11. A gear grinder comprising a rigid base member, bearings carried by the base member, a gear member journalled in the bearings, means to maintain with exactness the longitudinal position of the gear member relative to the base member, one or more pedestals resting on the base member, bearings carried by the pedestal or pedestals, one or more gear members, one for each pedestal, journaled in the pedestal bearings, and adapted to mesh with the first gear member, means to maintain with exactness the longitudinal position or positions of the gear member or members relative to the pedestal or pedestals, means to adjust the pedestal or pedestals longitudinally and laterally to secure a proper meshing of teeth and to obtain uniform grinding thereof, brake means associated with one gear member, and driving means associated with another gear member.

12. A gear grinder comprising a rigid base member, bearings carried by the base member, a gear member journalled in the bearings and having two rows of teeth, a thrust bearing for maintaining with precision the longitudinal position of the gear member relative to the base member, one or more pedestals resting on the base member, bearings carried by the pedestal or pedestals, one or more pedestal gear members, each gear member having two rows of teeth adapted to mesh with the teeth of the first member and being journalled in the bearings of a pedestal, a thrust bearing or bearings for maintaining with precision the longitudinal position or positions of the gear member or members relative to the pedestal or pedestals, means to adjust the pedestal or pedestals laterally and longitudinally to secure proper meshing of teeth and uniform grinding of the teeth in the rows, brake means associated with one gear member, and driving means associated with another gear member.

In testimony whereof, I have hereunto subscribed my name this 12th day of November, 1920.

JOHN H. MACALPINE. 

